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- What are the differences between metolazone and thiazide diuretics?
- What are metolazone and thiazide diuretics?
- What are the side effects of metolazone and thiazide diuretics?
- What is the dosage of metolazone vs. thiazide diuretics?
- What drugs interact with metolazone and thiazide diuretics?
- Are metolazone and thiazide diuretics safe to use while pregnant or breastfeeding?
What are the differences between metolazone and thiazide diuretics?
- Metolazone and thiazide diuretics are diuretics ("water pills") used to treat high blood pressure and fluid accumulation.
- Brand names for metolazone include Zaroxolyn, Mykrox, and Diulo.
- Side effects of metolazone and thiazide diuretics that are similar include low blood potassium (hypokalemia), low blood magnesium (hypomagnesemia), dizziness, lightheadedness, headache, weakness, and increased uric acid levels in the blood.
- Side effects of metolazone that are different from thiazide diuretics include low blood sodium (hyponatremia), high blood calcium (hypercalcemia), fatigue, nausea, vomiting, abdominal pain, constipation, and increased blood sugar in people with diabetes.
- Side effects of thiazide diuretics that are different from metolazone include blurred vision, loss of appetite, itching, stomach upset, increased sensitivity to sunlight, and sexual dysfunction.
What are metolazone and thiazide diuretics?
Metolazone is a diuretic ("water pill") used to treat high blood pressure and fluid accumulation. It works by blocking salt and fluid retention by the kidneys, thereby increasing urinary output of salt and water (diuresis). Although it is not a true thiazide, metolazone is chemically related to the thiazide class of diuretics which includes chlorthalidone (Hygroton) and hydrochlorothiazide, and works in a similar manner. Zaroxolyn is the original formulation of metolazone, and Diulo is similar. The absorption of these two drugs is relatively incomplete. Mykrox has more complete absorption and so less Mykrox needs to be given to have the same effects as a larger dose of Zaroxolyn or Diulo.
Thiazide diuretics (water pills) are used to treat high blood pressure (hypertension), congestive heart failure, and the accumulation of fluid and swelling (edema) of the body caused by conditions such as heart failure, chronic kidney failure, cirrhosis, corticosteroid medications, and nephrotic syndrome. Thiazides work by reducing the ability of the kidneys to reabsorb salt and water from the urine and into the body, thereby increasing the production and output of urine (diuresis). Examples of thiazide diuretics include chlorthalidone (Thalitone), hydrochlorothiazide (Microzide), and methyclothiazide.
What are the side effects of metolazone and thiazide diuretics?
Metolazone generally is well tolerated. Common side effects of metolazone are:
- Hypokalemia (low blood potassium)
- Hyponatremia (low blood sodium)
- Hypomagnesemia (low blood magnesium)
- Hypercalcemia (high blood calcium)
Thiazide diuretics, which are chemically related to metolazone, are known to increase the amount of uric acid in the blood. Precipitation of gout (which is associated with high uric acid) is rare. Metolazone can increase blood sugar in people with diabetes.
Side effects of thiazide diuretics are dose related and include:
Other side effects and adverse reactions include an increased sensitivity to sunlight, therefore avoid prolonged sun exposure.
Owing to their ability to increase the production of urine, these drugs may lower levels in the body of potassium and magnesium, which also are present in urine.
Thiazide diuretics may increase uric acid levels in blood.
Like other antihypertensive medications, thiazides cause sexual dysfunction.
What is the dosage of metolazone vs. thiazide diuretics?
The recommended dose is 2.5 to 5 mg for treating hypertension and 2.5 to 20 mg for treating edema.
Thiazide diuretics may come in oral tablet form. For example, Thalitone (chlorthalidone) is a common thiazide diuretic.
The optimal dose of Thalitone varies greatly from patient to patient. For high blood pressure, the recommended dose range is 25 to 100 mg daily. Most patients receive 12.5 to 25 mg daily.
Edema is treated with 50 to 100 mg daily or 100 mg every other day and the maximum dose is 200 mg daily.
Heart failure is treated with 12.5 to 100 mg daily.
What drugs interact with metolazone and thiazide diuretics?
Metolazone can reduce blood potassium and magnesium levels. This is especially true in patients who also are taking "loop" diuretics such as furosemide (Lasix), bumetanide (Bumex), and torsemide (Demadex). Low potassium and magnesium levels can lead to heart rhythm abnormalities, especially in patients taking digoxin (Lanoxin).
Steroids (for example, hydrocortisone) and nonsteroidal anti-inflammatory agents (NSAIDs) such as ibuprofen (Motrin), naproxen (Naprosyn), and nabumetone (Relafen) can reduce the effectiveness of metolazone by interfering with the excretion of salt and water.
Thiazide diuretics can lower potassium and magnesium blood levels since they are both eliminated in urine. Low levels of potassium and magnesium in the blood can result in abnormal heart rhythms, particularly in those who are also taking digoxin (Lanoxin) in addition to a thiazide. Thiazide diuretics can increase the risk of lithium (Eskalith, Lithobid) toxicity by reducing the kidney's ability to eliminate lithium in the urine.
Drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin), naproxen (Naprosyn), and nabumetone (Relafen) can reduce the effectiveness of thiazide diuretics in lowering blood pressure because they may reduce the ability of the kidneys to make urine, particularly in patients who have reduced kidney function.
People who have diabetes may have increased blood sugar levels when taking thiazide diuretics.
It is not recommended to use thiazide diuretics with dofetilide (Tikosyn), a drug used for treating abnormal heart rhythms, as this may increase the blood levels of dofetilide (Tikosyn) and cause abnormal heart rhythms. Thiazide diuretics can reduce how the body responds to norepinephrine and render norepinephrine less effective.
Are metolazone and thiazide diuretics safe to use while pregnant or breastfeeding?
Metolazone should not be used during pregnancy unless absolutely necessary.
Metolazone is excreted in breast-milk. Intense diuresis using metolazone may reduce the production of milk. Otherwise metolazone is considered safe to use during nursing if required by the mother.
Thiazide diuretics including Thalitone (chlorthalidone) cross the placenta and can cause jaundice in the fetus or newborn. Therefore, thiazide diuretics such as Thalitone should not be used during pregnancy unless absolutely necessary.
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Metolazone and thiazides are diuretics (water pills) used to treat high blood pressure and fluid accumulation. Side effects of metolazone and thiazide diuretics that are similar include low blood potassium (hypokalemia), low blood magnesium (hypomagnesemia), dizziness, lightheadedness, headache, weakness, and increased uric acid levels in the blood.
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Related Disease Conditions
High Blood Pressure (Hypertension)
High blood pressure (hypertension) is a disease in which pressure within the arteries of the body is elevated. About 75 million people in the US have hypertension (1 in 3 adults), and only half of them are able to manage it. Many people do not know that they have high blood pressure because it often has no has no warning signs or symptoms. Systolic and diastolic are the two readings in which blood pressure is measured. The American College of Cardiology released new guidelines for high blood pressure in 2017. The guidelines now state that blood normal blood pressure is 120/80 mmHg. If either one of those numbers is higher, you have high blood pressure. The American Academy of Cardiology defines high blood pressure slightly differently. The AAC considers 130/80 mm Hg. or greater (either number) stage 1 hypertension. Stage 2 hypertension is considered 140/90 mm Hg. or greater. If you have high blood pressure you are at risk of developing life threatening diseases like stroke and heart attack.REFERENCE: CDC. High Blood Pressure. Updated: Nov 13, 2017.
Congestive Heart Failure (CHF)
Congestive heart failure (CHF) refers to a condition in which the heart loses the ability to function properly. Heart disease, high blood pressure, diabetes, myocarditis, and cardiomyopathies are just a few potential causes of congestive heart failure. Signs and symptoms of congestive heart failure may include fatigue, breathlessness, palpitations, angina, and edema. Physical examination, patient history, blood tests, and imaging tests are used to diagnose congestive heart failure. Treatment of heart failure consists of lifestyle modification and taking medications to decrease fluid in the body and ease the strain on the heart. The prognosis of a patient with congestive heart failure depends on the stage of the heart failure and the overall condition of the individual.
Edema is the swelling of tissues as a result of excess water accumulation. Peripheral edema occurs in the feet and legs. There are two types of edema, non-pitting edema and pitting edema. Causes of pitting edema is caused by systemic diseases (most commonly involving the heart, liver, and kidneys), and medications. Local conditions that cause edema are thrombophlebitis and varicose veins. Edema or swelling of the legs, feet, ankles, and face are common during pregnancy. Idiopathic edema is edema in which the cause is not known. Pitting edema is scored on pitting edema measurement scales. Edema is generally treated with medication.
Heart failure (congestive) is caused by many conditions including coronary artery disease, heart attack, cardiomyopathy, and conditions that overwork the heart. Symptoms of heart failure include congested lungs, fluid and water retention, dizziness, fatigue and weakness, and rapid or irregular heartbeats. There are two types of congestive heart failure, systolic or left-sided heart failure; and diastolic or right-sided heart failure. Treatment, prognosis, and life-expectancy for a person with congestive heart failure depends upon the stage of the disease.
Hypertensive Kidney Disease
High blood pressure can damage the kidneys and is one of the leading causes of kidney failure (end-stage renal kidney disease). Kidney damage, like hypertension, can be unnoticeable and detected only through medical tests. If you have kidney disease, you should control your blood pressure. Other treatment options include prescription medications.
Preeclampsia (Pregnancy Induced Hypertension)
Preeclampsia is related to increased blood pressure and protein in the mother's urine. Preeclampsia typically begins after the 20th week of pregnancy. When preeclampsia causes seizures, it is termed "eclampsia" and is the second leading cause of maternal death of in the US. Preeclampsia is the leading cause of fetal complications. Risk factors for preeclampsia include high blood pressure, obesity, multiple births, and women with preexisting medical conditions such as diabetes, kidney disease, rheumatoid arthritis, lupus, or scleroderma. Pregnancy planning and lifestyle changes may reduce the risk of preeclampsia during pregnancy.
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